2 * Created by: Jason Wessel <jason.wessel@windriver.com>
4 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
11 #include <linux/kgdb.h>
12 #include <linux/kdb.h>
13 #include <linux/kdebug.h>
14 #include "kdb_private.h"
15 #include "../debug_core.h"
18 * KDB interface to KGDB internals
20 get_char_func kdb_poll_funcs[] = {
28 EXPORT_SYMBOL_GPL(kdb_poll_funcs);
31 EXPORT_SYMBOL_GPL(kdb_poll_idx);
33 static struct kgdb_state *kdb_ks;
35 int kdb_stub(struct kgdb_state *ks)
39 unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
40 kdb_reason_t reason = KDB_REASON_OOPS;
41 kdb_dbtrap_t db_result = KDB_DB_NOBPT;
45 if (KDB_STATE(REENTRY)) {
46 reason = KDB_REASON_SWITCH;
47 KDB_STATE_CLEAR(REENTRY);
48 addr = instruction_pointer(ks->linux_regs);
50 ks->pass_exception = 0;
51 if (atomic_read(&kgdb_setting_breakpoint))
52 reason = KDB_REASON_KEYBOARD;
54 for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
55 if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
56 reason = KDB_REASON_BREAK;
57 db_result = KDB_DB_BPT;
58 if (addr != instruction_pointer(ks->linux_regs))
59 kgdb_arch_set_pc(ks->linux_regs, addr);
63 if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
64 for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
67 if (bp->bp_addr == addr) {
71 * SSBPT is set when the kernel debugger must single step a
72 * task in order to re-establish an instruction breakpoint
73 * which uses the instruction replacement mechanism. It is
74 * cleared by any action that removes the need to single-step
77 reason = KDB_REASON_BREAK;
78 db_result = KDB_DB_BPT;
85 if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
86 ks->signo == SIGTRAP) {
87 reason = KDB_REASON_SSTEP;
88 db_result = KDB_DB_BPT;
90 /* Set initial kdb state variables */
91 KDB_STATE_CLEAR(KGDB_TRANS);
92 kdb_initial_cpu = atomic_read(&kgdb_active);
93 kdb_current_task = kgdb_info[ks->cpu].task;
94 kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
95 /* Remove any breakpoints as needed by kdb and clear single step */
97 KDB_STATE_CLEAR(DOING_SS);
98 KDB_STATE_CLEAR(DOING_SSB);
100 /* zero out any offline cpu data */
101 for_each_present_cpu(i) {
102 if (!cpu_online(i)) {
103 kgdb_info[i].debuggerinfo = NULL;
104 kgdb_info[i].task = NULL;
107 if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
108 ks->pass_exception = 1;
109 KDB_FLAG_SET(CATASTROPHIC);
111 if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
112 KDB_STATE_CLEAR(SSBPT);
113 KDB_STATE_CLEAR(DOING_SS);
115 /* Start kdb main loop */
116 error = kdb_main_loop(KDB_REASON_ENTER, reason,
117 ks->err_code, db_result, ks->linux_regs);
120 * Upon exit from the kdb main loop setup break points and restart
121 * the system based on the requested continue state
123 kdb_initial_cpu = -1;
124 kdb_current_task = NULL;
125 kdb_current_regs = NULL;
126 KDB_STATE_CLEAR(PAGER);
127 kdbnearsym_cleanup();
128 if (error == KDB_CMD_KGDB) {
129 if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
130 KDB_STATE_CLEAR(DOING_KGDB);
131 KDB_STATE_CLEAR(DOING_KGDB2);
133 return DBG_PASS_EVENT;
135 kdb_bp_install(ks->linux_regs);
136 dbg_activate_sw_breakpoints();
137 /* Set the exit state to a single step or a continue */
138 if (KDB_STATE(DOING_SS))
139 gdbstub_state(ks, "s");
141 gdbstub_state(ks, "c");
143 KDB_FLAG_CLEAR(CATASTROPHIC);
145 /* Invoke arch specific exception handling prior to system resume */
146 kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
147 if (ks->pass_exception)
148 kgdb_info[ks->cpu].ret_state = 1;
149 if (error == KDB_CMD_CPU) {
150 KDB_STATE_SET(REENTRY);
152 * Force clear the single step bit because kdb emulates this
153 * differently vs the gdbstub
155 kgdb_single_step = 0;
156 dbg_deactivate_sw_breakpoints();
157 return DBG_SWITCH_CPU_EVENT;
159 return kgdb_info[ks->cpu].ret_state;
162 void kdb_gdb_state_pass(char *buf)
164 gdbstub_state(kdb_ks, buf);